The present invention is directed to magnetic resonance imaging (MRI) devices, and, particularly, to an improved technique for reconfiguring MRI devices.
MRI technology permits the noninvasive imaging of internal details within an object, such as a living person. The scientific and diagnostic values of this technology are set forth in numerous prior art patents and articles, e.g., the many innovations of Dr. Raymond V. Damadian, the discoverer of this technology, as noted in the patent records.
Magnetic resonance imaging, also called nuclear magnetic resonance (NMR) imaging, is a non-destructive method for the analysis of materials and is used extensively in medical imaging. It is completely non-invasive and does not involve ionizing radiation. In very general terms, nuclear magnetic moments of individual atoms within a portion of a body are excited at specific spin precession frequencies which are proportional to the local magnetic field. The radio frequency (RF) signals resulting from the precession of these spins are received using pickup coils. By manipulating the magnetic fields, an array of signals is provided representing different regions of the volume. These are combined to produce a volumetric image which characterizes the nuclear spins within the body.
In MRI, a body is subjected to a constant magnetic field. Another magnetic field, in the form of electromagnetic (RF) pulses, is applied orthogonally to the constant magnetic field. The RF pulses have a particular frequency that is chosen to affect particular atoms (typically hydrogen) in the body. The RF pulses excite the atoms, increasing the energy state of the atoms. After the pulse, the atoms relax and release RF emissions, corresponding to the RF pulses, which are measured and displayed.
At the heart of an MRI device is a controller, which controls the pulse sequences, retrieves and stores the relaxation emissions, and sends this data to a computer which processes and displays the data. The controller may be a complex programmable logic device (CPLD), which includes a series of embedded array blocks (EABs) used to implement various memory and complex logic functions, as is understood to those skilled in the art. The respective EABs are physically configured in a desired manner to eliminate the need for discrete chips. The controller might also be another type of programmable logic device, such as a field programmable gate array (FPGA) or application specific integrated circuit (ASIC). It should also be understood that CPLD, FPGA, and ASIC boards are statically configured, ie., the board is so configured and stays so configured during the lifetime of use.
As noted, the hardware in present MRI systems is fixed. In particular, either the hardware is made of discrete logic or the respective CPLDs, FPGAs, ASICs, etc. that constitute the boards are physically configured and remain that way thereafter until obsolete.
Thus, in prior art techniques, the hardware is only designed to enable a generic MRI sequence run. Any newly-created sequence runs must, therefore, be designed to run on the generic configuration even if that configuration is inefficient or incorrect.
There is, therefore, a present need for an improved system and methodology for ameliorating or eliminating the inefficiencies in prior art MRI techniques, enabling MRI operators to readily reconfigure the hardware for a variety of potential sequences and hinder device obsolescence.
The present invention provides a method and apparatus to improve the efficiency of an MRI apparatus by allowing the controller of the MRI to be remotely reconfigured, allowing modification and upgrade of the hardware configuration of the controller. For complex or innovative pulse sequences, a customized hardware configuration of the controller may be necessary; for optimization of digital signal processing of the received data, reconfiguring the hardware configuration of the controller to perform the digital signal processing may be desirable.